/**
 * [dateAddDays 从某个日期增加n天后的日期]
 * @param  {string} dateStr  [日期字符串]
 * @param  {int} dayCount [增加的天数]
 * @param  {reduce} False为加 True为减
 * @return {string}[增加n天后的日期字符串]
 */
function dateAddOrReduceDays(dateStr,dayCount,reduce) {
    if (isNotEmpty(dateStr)){
        var tempDate=new Date(dateStr.replace(/-/g,"/"));
        var resultDate;
        if (reduce === false){
            resultDate =new Date((tempDate/1000+(86400*dayCount))*1000);
        }else {
            resultDate =new Date((tempDate/1000-(86400*dayCount))*1000);
        }
        return resultDate.getFullYear()+"-"+(resultDate.getMonth()+1)+"-"+(resultDate.getDate());//将日期转化为字符串格式
    }
}
